Radeon HD 3850 256MB vs Radeon HD 7870

Intro

Compare all of that to the Radeon HD 7870, which has a clock speed of 1000 MHz and a GDDR5 memory frequency of 1200 MHz. It also uses a 256-bit bus, and makes use of a 28 nm design. It is comprised of 1280 SPUs, 80 Texture Address Units, and 32 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 3850 256MB		75 Watts
Radeon HD 7870		175 Watts
	Difference: 100 Watts (133%)

Memory Bandwidth

Performance-wise, the Radeon HD 7870 should theoretically be quite a bit better than the Radeon HD 3850 256MB overall. (explain)

Radeon HD 7870		153600 MB/sec
Radeon HD 3850 256MB		52992 MB/sec
	Difference: 100608 (190%)

Texel Rate

The Radeon HD 7870 should be much (about 649%) more effective at AF than the Radeon HD 3850 256MB. (explain)

Radeon HD 7870		80000 Mtexels/sec
Radeon HD 3850 256MB		10688 Mtexels/sec
	Difference: 69312 (649%)

Pixel Rate

The Radeon HD 7870 should be quite a bit (more or less 199%) more effective at full screen anti-aliasing than the Radeon HD 3850 256MB, and also will be able to handle higher screen resolutions more effectively. (explain)

Radeon HD 7870		32000 Mpixels/sec
Radeon HD 3850 256MB		10688 Mpixels/sec
	Difference: 21312 (199%)

Please note that the above 'benchmarks' are all just theoretical - the results were calculated based on the card's specifications, and real-world performance may (and probably will) vary at least a bit.

Price Comparison

Specifications

Memory Bandwidth: Memory bandwidth is the max amount of information (in units of megabytes per second) that can be transported past the external memory interface in one second. It's calculated by multiplying the card's bus width by the speed of its memory. In the case of DDR type RAM, it must be multiplied by 2 again. If DDR5, multiply by ANOTHER 2x. The higher the memory bandwidth, the better the card will be in general. It especially helps with AA, High Dynamic Range and high resolutions.

Texel Rate: Texel rate is the maximum texture map elements (texels) that are applied per second. This figure is calculated by multiplying the total amount of texture units of the card by the core clock speed of the chip. The better the texel rate, the better the graphics card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in a second.

Pixel Rate: Pixel rate is the maximum number of pixels that the graphics card can possibly record to the local memory in a second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the number of Render Output Units by the the core clock speed. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel output rate also depends on quite a few other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the ability to reach the maximum fill rate.